Per RFC-WS-6 §Q1 v1.3 addition 4. Configurable deadline for FormBindingApplicator::apply(). Default 5 seconds catches the long tail of slow applies before they hang the public flow. Tunable per environment via FORM_BUILDER_APPLY_DEADLINE_SECONDS. Consumed by ApplyBindingsOnFormSubmit::handle's withDeadline() call (landed in Phase B). Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>